Today, vehicles are widespread and traffic is increasing. Therefore road safety is a major problem. To solve traffic problems, special attention is given to develop systems that can reduce the number and severity of road events. Additionally, the spread of wireless communication and mobile devices creates self-organizing networks, which are ad-hoc, that do not require a pre-established infrastructure and provide users with everywhere communication capability and information access. The application of ad-hoc networks for Inter-Vehicle Communications (IVC) is in the focus of various research projects. One research topic in this context is the question of appropriate data traffic models for those networks. This paper is focused on applications and data traffic models suitable for ad-hoc network based IVC. Based on existing and future applications for IVC the constraints for suitable models are developed.